cold weather + engine light

[johnnybate]

would extreme cold weather(30 below freezing) cause the check engine light to come on?

i started the car to warm it up and the light did not come on, but 15 minutes later when i went out it was on.

[yogi_123rd]

It possibly can happen. The real question is does the CEL stay on after driving it a bit which would indicate a real problem.
I have noticed that the CES has come on a few times in extreme cold weather after about 5-10 minutes of starting the car with an Oxygen Sensor Fault code. It would eventually go out after driving it a bit. I know the ECM will delay doing the Oxy Sensor check after startup to give time for the exhaust system to reach operating temperature of 700 degrees.

[johnnybate]

it went off after 20-25 mins so i guess im good

[sallisonbrown]

Originally Posted by johnnybate

it went off after 20-25 mins so i guess im good

The "Check Engine" probably came on due to the extremely low temperature not allowing the fuel to atomize corectly and it read a overly rich condition.

GM has anticipated this happening and instead of the light staying on it is set to clear itself once the condition improves (complete warmup). Usually this is after shut down and subsequent start up when the system reads normal fuel atomization in the injectors and cylinders. I've taken my 2000 LeSabre into the shop and paid $39.95 to have the code read and reset before I looked in my Owners manual and realized what was happening.

Good Luck,
Steve